In our daily lives, we are heavily reliant on the use of classic energy sources such as coal, oil and natural gas for the production of electricity, heat and transportation. Since these resources are limited, it is time to look for ways to integrate renewable energy sources (solar, biomass, wind, etc.) into our daily lives. But this is not the only way to reduce dependence on conventional forms of energy. Another way is to embrace the concept of energy efficiency, which means optimising the energy that we are already using, for the consequences are borne by all of us, even if we are not aware of it right now. By means of simple actions (e.g. replacing a traditional lighting system with an LED or more efficient system or purchasing motor vehicles with low CO2 emissions and therefore lower fuel consumption, etc.), we can actively contribute to environmental protection and reduce costs at the same time